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PC to arcade monitor without image (Radeon HD5450)
mjnman:
I built a cable from VGA to arcade monitor with connetions in image attachment.
I bought a Radeon HD5450 PCI-E card and connected to arcade monitor with the cable, CA&G VI2100 15khz monitor.
I patched the linux kernel 5.6 with 15khz video patches and configured boot grub and xorg.conf.
After the boot I can hear the sound but always without image.
I checked a lot of time the cable pinout but I can confirm that is OK.
What can I check for the video output problem?
buttersoft:
If you have an LCD or other VGA monitor capable of 15kHz you could try plugging it in. In fact, even if your LCD is not 15kHz capable, plug it in anyway and see what gives - it'll tell you "out of range" if the signal is 15kHz. You can also put a multimeter on each sync line and check the frequency it's outputting. V-sync should be ~60Hz presumably, and H-sync should be 15kHz.
After that, does your monitor have the ability to take separate H- and V-sync at 15kHz, or does it want Composite-sync? (Just because it says V-sync at one input doesn't automatically mean it works, the same PCB might have variants). Are there any jumpers or switches to affect this on the chassis? How about voltage tolerance? What voltage are you outputting sync at? VGA is TTL level sync, or a 5V square wave. And what RGB level does the monitor want? Most arcade monitors want about 1.5Vp-p or higher, and VGA is only 0.7Vp-p. The image would often be dim, but maybe it's not showing up. What happens when you turn up the screen pot with the PC connected, does any image appear, or just the slanted retrace lines over a grey screen? Leaving those lines slightly visible, does plug and unplugging the video change anything? And plugging and unplugging either or both sync lines alone?
mjnman:
Yes I have a separate H- and V-sync at 15kHz. I didn't see any jumpers or switches. I connected same sync in pin 6, H sync, but always without immage. I tried boot with "GroovyArcade live-CD New Release 2020" and all option (VGA-X of course) boot but always black sceen.
I think is a voltage problem.
In attachment the board manual.
Zebidee:
Try connecting VGA pin 10 (sync ground) to the ground wire
mjnman:
I tried to connect 5 and 10 pin together (VGA side) and then to the ground (CGA side) but same result. No video image.
Maybe is it a low voltage on RGB vga side? from monitor manual the video signal vpp should be 2-5 vpp